The present invention generally relates to medical devices for introducing therapeutic or diagnostic instruments, such as a blood filter, occluder, atherectomy device, stents, angiographic catheters, and pressure monitors to a vessel or cardiac tissue. More particularly, the devices include an obturator having a retractable blade for making an incision on a tissue, thereby allowing convenient and efficient delivery of medical instrument(s) through a single incision on the vessel or cardiac tissue.
During various cardiothoracic, pulmonary, and vascular surgeries, including coronary artery bypass grafting, heart valve repair or replacement, atrial or ventricular septal defect repair, angioplasty, atherectomy, aneurysm repair, and pulmonary thrombectomy, cannulation of a patient""s vessel(s) are often required to provide vascular access for delivery of various diagnostic and therapeutic devices. In a conventional approach, incisions generally made by a surgical blade are needed for introduction of medical device(s). For example, during coronary artery bypass grafting (CABG) surgeries, cardiopulmonary bypass is established by cannulation of the aorta to provide circulatory isolation of the heart and coronary blood vessels. Two incisions on the aorta may be required, i.e., one for insertion of the arterial cannula and another for insertion of a balloon occluder to provide coronary isolation from the peripheral vascular system. Once the incisions are made on the aorta, the devices often remain in the aorta throughout the entire procedure despite only being used intermittently, e.g., the cardioplegia catheter.
Due to significant mortality and morbidity associated with the conventional CABG surgeries from the use of cardiopulmonary bypass for circulatory support and the traditional method of access by median sternotomy, minimally invasive concepts recently have been adopted to make cardiothoracic procedures less invasive. Minimally invasive alternatives include the minimally invasive direct CABG procedure in which the operation is performed through minimal access incisions, eliminating cardiopulmonary bypass. The second alternative is to perform the procedure through minimal access incisions, and cardiopulmonary support is instituted through an extra thoracic approach, i.e., the port access approach. The third alternative is to perform the procedure on a beating heart which allows greater access for more extensive revascularization, i.e., the xe2x80x9coff pumpxe2x80x9d sternotomy approach. In any of the minimally invasive alternatives, the space allowed for multiple incisions and device insertion is limited.
The disadvantages associated with the conventional or minimally invasive approach are that (1) by having multiple devices inserted in the aorta, the space available for the surgeon to perform procedures is limited, and (2) the aorta is traumatized as a result of multiple incisions, which may result in aortic dissection, aortic wall hematoma, and/or embolization of calcium plaque from the aortic wall. The greater the aortic trauma, the higher the perioperative morbidity a patient will endure.
Accordingly, there is a need for devices and methods which provide access to a vessel or body cavity and allow introduction of medical instrument(s) through a single incision, and particularly through a single introducer by exchanging medical instruments with minimal blood loss. A further need exists for devices and methods to assist with making an incision in a body cavity for the purpose of introducing an introducer while minimizing blood loss, and with maximum convenience for the physician.
The present invention provides introducers for introducing medical devices into a body tissue, such as a vessel, or cardiac tissue, for performing multiple functions including perfusion, drug deliver, fluid infusion, atherectomy, fluid pumping, aspiration, suturing, stapling, collagen or fibrin delivery, delivery of pacing leads, angiographic catheters, valvuloplasty catheters, and electrode catheters, internal vessel segregating or isolating dams, endoscopic cameras, pressure monitors, shunts, stents, graft delivery, and other endovascular and endoscopic devices. Obturators are also provided for creating an incision in body tissue. Although the introducers and obturators disclosed herein are most useful in cardiovascular procedures, they can also be used in introducing medical devices into other body cavities, e.g., gastrostomy tube placement, and abdominal or pelvic laporoscopy.
In a first embodiment, the introducer comprises an elongate tubular member and a device connector releasably attached to a proximal end of the tubular member. The objective here is to allow for the exchange of endovascular devices through a single tubular introducer. A distal end of the tubular member is adapted to enter a body tissue. The proximal end of the tubular member has, in certain embodiments, a longitudinal alignment slot extending distally from the proximal end. The device connector has a lumen communicating with a first end and a second end. The lumen is adapted to receive a medical device. A medical device is inserted and secured in the lumen of the device connector before it is inserted through the lumen of the tubular member. The connector also includes an alignment pin adapted to engage the alignment slot of the tubular member, and is shaped to engage the proximal end of the tubular member by operating a release lever.
In another embodiment, the introducer includes a second tubular member mounted adjacent to the first tubular member. The second tubular member has a proximal end with a proximal port, a distal end with a distal port and a lumen communicating between the proximal and distal ports. The second tubular member also includes a second connector having a lumen adapted to reversibly engage the proximal end of the second tubular member, and to receive a second medical device through the second connector lumen. The second medical device is inserted through the second tubular member and is deployable through the distal port of the second tubular member. In certain embodiments, the distal port of the first tubular member communicates with the distal port of the second tubular member, such that the first and second medical devices are deployed through a common distal port. In other cases, the lumens remain separate and communicate with separate distal ports.
The lumens of the tubular member and the device connector are also adapted to receive an obturator for making an incision on a body tissue. In a first embodiment, the obturator comprises an elongate tubular member having proximal and distal ends. The distal end has a slot which extends proximally, and includes a blade which connects to a distal end of an actuating mechanism. The actuating mechanism generally includes a force-biasing element, such as a spring, a retaining element, and a release. The blade can be advanced distally to incise a tissue, or retracted to a position within the slot by operating the actuating mechanism from the proximal end of the elongate tubular member. The obturator is insertable through the lumen of the introducer or can be used independently to incise a body tissue, e.g., a vessel, cardiac tissue, gallbladder, or stomach.
In a first method of using the obturators and introducers described above for introduction of a medical device, the obturator, having the blade in a retracted position, is inserted through the lumen of the introducer to create an incision on a body tissue. The blade extends distally beyond the distal end of the obturator by operating the actuating mechanism at the proximal end of the obturator, such that the actuating mechanism slides distally against the force-biasing element and is retained in a distal position. After an incision is made in the body using the blade, the introducer is inserted though the incision. The actuating mechanism is then released and slides proximally to retract the blade into a position within the slot, and the obturator is removed from the introducer. A hemostatic valve mounted within the lumen of the introducer prevents blood loss. A medical device is inserted through the lumens of the device connector and secured, and the device is then inserted into the tubular member of the introducer. The device is then advanced into the body tissue. When present, the alignment pin is aligned with the longitudinal slot of the tubular member, and the device connector snaps into engagement with the proximal end of the tubular member. In certain embodiments, a suture flange is provided on the distal end of the introducer, and sutures can be placed on the flange to stabilize the introducer and the medical device onto the body tissue.
In another method, the incision on the body tissue is created by holding the obturator directly adjacent the body tissue and operating the actuating mechanism to advance the blade without placing the obturator in the lumen of the introducer. After the incision is made, the introducer is inserted through the incision for introducing medical devices.